Method op making high-silicon



A. PINKERTON.

METHOD OF MAKING HIGH SILICON SHEETS AND PLATES.

APPLICATION FILE D OCT. 20. 1920.

1,396,052, Patented Nov. 8, 1921.

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Wifnees's es fizven for.

M MUM UNITED STATES PATENT OFFICE.

ANDREW PINKERTON, OF BEN AVON, PENNSYLVANIA, ASSIGNOR TO AMERICAN SHEET AND TIN PLATE COMPANY, OF PITTSBURGH, PENNSYLVANIA, A 003- PORATION OF NEW JERSEY.

METHOD OF MAKING HIGH-SILIGON SHEETS AND PLATES.

Specification of Letters Patent.

Patei'ited Nov. *8, 1921.

Application filed October 20, 1920. Serial No. 418,180.

and Plates, of which the fOllOWiTlg is a specification.

My invention relates to the manufacture of high silicon steel sheets and plates, a rolled steel product having a silicon content much greater than in ordinary steel,

and used practically to an exclusive extent in making parts of electric meters, transformers, motors, and generators, and hire electrical apparatus.

One object of my invention is the provisionof a novel method of making sheets and plates of high silicon teel whereby the presence of loosely adherent scale on the surfaces of the finished sheets or plates is avoided and overcome.

Anotherobject of the invention is to pro-- vide an improved method of making sheets whereby a product is obtained which will withstand the severe treatment to which the sheets and plates are subjected in the later punching or sheering operations by which the sheets or plates are formed into parts of electrical apparatus.

Another object of the invention is to improve the physical qualities without lessening the electrical properties of high silicon sheets or plates.

Still further objects of the invention will be made apparent by reference to the detailed description of my invention as set forth in the specification and as particularly pointed out in the appended claims.

It is found that high silicon sheets as made heretofore have a loose scale on the surfaces thereof which becomes detached on very moderate bending of the sheets, and

forms a defect causing frequent complaint by users of this grade of material, although accepted by the trade as inherent to such material.

In making high silicon sheets by existing methods the sheet bars are rolled into sheets, the sheets are sheared and the packs are opened in the usual and well known manner. The sheets are then cold rolled and directly following the cold rolling operation are annealed in preparation for shipment, provided satlsfactory electrical tests are obtained.

The surfaces of sheets made in this man;

ner always have a scale thereon which is readily detached upon very moderate bend mg, and in shearing and punching the sheets. The presence of this easily loosened scale on the sheets is very objectionable and becomes serious when usedin making electrical apparatus having moving parts such as electric meters.

The removal of the scale from the annealed sheets by pickling has been attempted, but without success. One reason for'the failure is that the scale on highsilicon sheets and plates differs in composition fromthat on ordinary rolled steel sheets and plates, by having moresilicon and less iron oxid. While the scale can be removed from the'annealed high silicon sheets. and plates by a pickling operation, it is found that the fuly pickled sheets are greatly re duced in thickness in the parts thereof where the scale is first removed, (even to the extent of forming holes in the sheets), and the sheets are found to be very irregu lar in thickness, which lessens their value making parts of electrical apparatus. In the majority of cases the complete removal of the scale is effected only at the cost of such excessive pickling as to become destructive to the sheets and plates, and therefore to be prohibitive.

I have discovered that by pickling the sheets and plates, after opening the pack and before the commencement of the annealing operation, a product is obtained which is of substantially uniform thickness, is en tirely free from loosely adhering scale, and which has surfaces that will not peel and do not crack when the sheets and plates are later subjected to bending, shearing, or punching operations.

Referring now to the drawing forming part of this specification, Figure 1 is a diagrammatic plan showing one arrangement of apparatus adapted for use in carrying out my improved method. 7

Fig. 2 is a sectional side elevation of the apparatus of Fig. 1.

In practising my improved method the sheet bars are heated in a furnace 2, and the heated bars are rolled in a hot mill 3.

In rolling sheets, the partly rolled bars are doubled to form a pack, and in rolling the. lighter gages of sheets the packs will be again doubled. The so-formed packs, after the completion of the rolling operation, are cut to length and width by shears l, and the sheared packs are then opened by the pack opening apparatus 5. The sheets are then passed between cold rolls 6. The foregoing steps, which are old, are employed in the old method and also in my improved method.

In carrying out the later steps of my improved method, each sheet after comple tion of the cold rolling operation, is passed through a pickling bath 7 and pickled so as to completely remove any scale on the surfaces of the cold rolled sheets, and, the pickled sheets after being passed through the'bath 8 and washed so as to remove all traces of acid, are again assembled in packs, and the packs are placed in annealing boxes. The filled annealing boxes are then transferred to an annealing furnace 9, and the sheetsare then annealed therein in the-usual manner. In some cases the annealed mate rials are deoxidized by putting natural gas into the annealing boxes while the'plates are being cooled therein from the high temperature to which they are heated in the annealing operation.

The so-formed sheets when cooled and removed fr'om the annealing boxes will be found to be of substantially uniform thickness and to have a smooth surface which is free of any loosely adherent scale.

removing the scale by pickling the sheets and plates after the annealing operation is completed.

Various modifications in the making of the sheets, which will suggest themselves, may

he made without departing from my invention as defined in the appended claims.

I claim 1. In the manufacture of high silicon steel sheets and plates. the steps consisting in cold rolling the previously hot rolled sheets and plates, then pickling the cold rolled material, and then annealing the pickled material.

2. In the manufacture of high silicon steel sheets and plates, the steps consisting in cold rolling the previously hot rolled sheets or plates, then pickling the cold rolled sheets or plates, and then annealing and (leoxidizing the pickled sheets or plates.

3. In the manufacture of high silicon steel sheets and plates, the step which consists in pickling the sheets and plates subsequent to cold rolling and prior to annealing said sheets or plates.

In testimony whereof, I have hereunto signed my name.

ANDREW PINIQERTON. 

